Abstract: An inversion based calibration method for downhole electromagnetic tools includes processing an inversion of a formation model using acquired electromagnetic measurement data to obtain formation parameters and calibration parameters for at least one measurement array.

Abstract: Systems and methods for imaging properties of subterranean formations in a wellbore include a formation sensor for collecting currents injected into the subterranean formations and a formation imaging unit. The formation imaging unit includes a current management unit for collecting data from the currents injected into the subterranean formations and a formation data unit for determining at least one formation parameter from the collected data. The formation imaging unit also includes an inversion unit for determining at least one formation property by inverting the at least one formation parameter. The inversion unit is suitable for generating an inverted standoff image and an inverted permittivity image for comparison with a composite image of the formation imaging unit.

Abstract: A distributed computing system and method is described herein. The system and method employ a server node, compute nodes, a network file system server providing shared data storage resources, and client systems. The server node receives and processes a document submitted by a client system. The document specifies a job including a number of compute tasks that are to be executed in a distributed manner by the compute nodes, data for at least one compute task of the job, a shared directory on the network file system server, and a collection of the compute nodes that have access to the shared directory. The server node stores the data for the compute task of the job into the shared directory. At least one compute node that belongs to the collection accesses the directory to process the data for the compute task of the job for execution of the compute task.

Abstract: The present disclosure relates to a method to determine a formation property of a subsurface formation. A downhole logging tool having two or more antennas, at least two of the antennas having a transversely-sensitive element and an axially-sensitive element is provided. Azimuthally-sensitive measurements are obtained using the antennas of the downhole logging tool. The measurements are fitted to a Fourier series having Fourier coefficients that include channel gains, if any. A DC component, a first harmonic component, and a second harmonic component are determined from the Fourier series, a measurement type is determined using the DC component, the first harmonic component, and/or the second harmonic component, and the formation property of the subsurface formation is determined using the determined measurement type.

Abstract: A multi-step electromagnetic inversion method is provided for determining formation resistivity, anisotropy and dip. An electromagnetic logging tool is used to obtain non-directional, anisotropy, and directional (including symmetrized and anti-symmetrized resistivity measurements) in a formation using an electromagnetic logging tool. Bed boundaries of the formation are first identified. A horizontal resistivity profile is obtained using the non-directional resistivity measurements, and a vertical resistivity profile is obtained using the anisotropy resistivity measurements. The vertical resistivity profile is improved using the directional resistivity measurements, while dip values are also obtained via an inversion using the directional resistivity measurements. Then, an inversion for each of vertical resistivity, horizontal resistivity, dip values, and bed boundaries is performed using all of the non-directional, anisotropy, and directional resistivity measurements to obtain a formation model.

Abstract: Methods and apparatus for characterizing a subterranean formation traversed by a wellbore including collecting data from the formation using a tool wherein the tool collects data to form an azimuthal image, characterizing a section of the formation comprising data and images acquired in a high angle wellbore section or horizontal wellbore section using a parametric model, and performing an inversion using apparent densities and volumetric photoelectric factor images to build a formation model wherein the inversion is tailored for high angle wellbore sections and/or horizontal wellbore sections.

Abstract: A system and method for imaging properties of subterranean formations in a wellbore is provided. The system comprises a formation sensor for collecting currents injected into the subterranean formations, the formation sensor positionable on a downhole tool deployable into the wellbore. The system comprises a controller for controlling the formation sensor and a formation imaging unit. The formation imaging unit comprises a current management unit for collecting data from the currents injected into the subterranean formations, the currents having at least two different frequencies. The formation imaging unit comprises a drilling mud data unit for determining at least one drilling mud parameter, a formation data unit for determining at least one formation parameter from the collected data, and an inversion unit for determining at least one formation property by inverting the at least one formation parameter.

Abstract: A system and method for imaging properties of subterranean formations in a wellbore is provided. The system comprises a formation sensor for collecting currents injected into the subterranean formations, the formation sensor positionable on a downhole tool deployable into the wellbore. The system comprises a controller for controlling the formation sensor and a formation imaging unit. The formation imaging unit comprises a current management unit for collecting data from the currents injected into the subterranean formations, the currents having at least two different frequencies. The formation imaging unit comprises a drilling mud data unit for determining at least one drilling mud parameter, a formation data unit for determining at least one formation parameter from the collected data, and an inversion unit for determining at least one formation property by inverting the at least one formation parameter.

Abstract: A system and method for imaging properties of subterranean formations in a wellbore is provided. The system comprises a formation sensor for collecting currents injected into the subterranean formations, the formation sensor positionable on a downhole tool deployable into the wellbore. The system comprises a controller for controlling the formation sensor and a formation imaging unit. The formation imaging unit comprises a current management unit for collecting data from the currents injected into the subterranean formations, the currents having at least two different frequencies. The formation imaging unit comprises a drilling mud data unit for determining at least one drilling mud parameter, a formation data unit for determining at least one formation parameter from the collected data, and an inversion unit for determining at least one formation property by inverting the at least one formation parameter.

Abstract: LWD measurements to be used for proactive well placement while drilling a high angle or horizontal wellbore in a reservoir are defined. An initial reservoir model is provided and a section is extracted for a planned wellbore trajectory. A secondary model is generated for the planned trajectory. An area of interest is identified where statistical uncertainty is high. Possible causes of the statistical uncertainty are identified that are not present in the initial reservoir model. A set of parameters are defined based on the possible causes of statistical uncertainty. The area of interest is logged with LWD tool. Sensitivities of the LWD tool response to a subset of parameters are evaluated by performing tertiary model for a range of the subset of parameters. The most sensitive parameters from the subset of parameters and corresponding measurements are identified. LWD measurements are defined based on the most sensitive parameters.

Abstract: Compositions of lost circulation materials are provided that are useful for identifying the location of fluid loss in a wellbore. The compositions include additives which enhance a property of the composition such that they can be detected by an LWD or MWD tool capable of measuring the property when the composition is deployed in a region of loss, and can be distinguished by the LWD or MWD tool from the formation and mud fluid. Methods are also provided for using the composition to detect the location of fluid loss and for controlling the loss of fluid from the wellbore. The methods involve deploying the compositions in loss regions by adding the compositions to drilling mud, and measuring a property of the compositions using an LWD or MWD tool.

Abstract: A method is provided for determining formation resistivity, anisotropy and dip from wellbore measurements includes moving a well logging instrument through subsurface formations. The instrument includes longitudinal magnetic dipoles and at least one of tilted and transverse magnetic dipoles. Formation layer boundaries and horizontal resistivities of the formation layers are determined from longitudinal magnetic dipole measurements. Vertical resistivities of the formation layers are determined by inversion of anisotropy sensitive measurements. Improved vertical resistivities of the formation layers and dips are determined by inverting symmetrized and anti-symmetrized measurements. Improved vertical resistivities, improved boundaries and improved dips are determined by inversion of the all dipole measurements. Improved horizontal resistivities, further improved layer boundaries and further improved dips are determined by inversion of all dipole measurements.

Abstract: A method for determining electromagnetic induction properties of subsurface rock formations includes determining an eccentering angle of a well logging instrument disposed in a wellbore. The instrument includes at least one triaxial induction transmitter and at least one triaxial induction receiver. The eccentering angle is determined from symmetric cross component measurement differences. The triaxial induction measurements made from the at least one receiver are rotated to an apparent eccentering angle of zero. At least one electromagnetic induction property is determined from the rotated triaxial induction measurements.

Abstract: A system and method for imaging properties of subterranean formations in a wellbore is provided. The system comprises a formation sensor for collecting currents injected into the subterranean formations, the formation sensor positionable on a downhole tool deployable into the wellbore. The system comprises a controller for controlling the formation sensor and a formation imaging unit. The formation imaging unit comprises a current management unit for collecting data from the currents injected into the subterranean formations, the currents having at least two different frequencies. The formation imaging unit comprises a drilling mud data unit for determining at least one drilling mud parameter, a formation data unit for determining at least one formation parameter from the collected data, and an inversion unit for determining at least one formation property by inverting the at least one formation parameter.

Abstract: The present disclosure relates to a method to determine a formation property of a subsurface formation. A downhole logging tool having two or more antennas, at least two of the antennas having a transversely-sensitive element and an axially-sensitive element is provided. Azimuthally-sensitive measurements are obtained using the antennas of the downhole logging tool. The measurements are fitted to a Fourier series having Fourier coefficients that include channel gains, if any. A DC component, a first harmonic component, and a second harmonic component are determined from the Fourier series, a measurement type is determined using the DC component, the first harmonic component, and/or the second harmonic component, and the formation property of the subsurface formation is determined using the determined measurement type.

Abstract: A method is provided for determining formation resistivity, anisotropy and dip from wellbore measurements includes moving a well logging instrument through subsurface formations. The instrument includes longitudinal magnetic dipoles and at least one of tilted and transverse magnetic dipoles. Formation layer boundaries and horizontal resistivities of the formation layers are determined from longitudinal magnetic dipole measurements. Vertical resistivities of the formation layers are determined by inversion of anisotropy sensitive measurements. Improved vertical resistivities of the formation layers and dips are determined by inverting symmetrized and anti-symmetrized measurements. Improved vertical resistivities, improved boundaries and improved dips are determined by inversion of the all dipole measurements. Improved horizontal resistivities, further improved layer boundaries and further improved dips are determined by inversion of all dipole measurements.

Abstract: An orientation vector, referred to hereinafter as the “geosteering vector,” is directed to the more conductive formation area within the DOI of the tool and away from the more resistive formation areas. Accordingly, drilling in a direction opposite the geosteering vector leads to more resistive formation. Also, the disclosed geosteering vectors obtained from the real and imaginary components will not align with each other for non-planar formations and therefore the misalignment of the geosteering obtained from real and imaginary components is indicative of a non-planar formation. A superposition method is disclosed which can be used to calculate electromagnetic (EM) couplings in a non-planar geometry formation (as well as in a planar geometry formation) in real time, without requiring two or three dimensional modeling calculations.

Abstract: Methods for three-dimensionally characterizing a reservoir while drilling a high angle or horizontal wellbore through the reservoir are disclosed. An initial reservoir model for the reservoir is selected and a section is extracted for a planned trajectory of the wellbore. A secondary model is generated by performing secondary modeling for at least part of the planned trajectory. An area of interest is identified within the secondary model where statistical uncertainty is high. Possible causes of the statistical uncertainty are identified for the area of interest within the secondary model that are not present or accounted for in the initial reservoir model. A set of parameters for the area of interest are defined at that are based on the possible causes of statistical uncertainty. The area of interest is logged with at least one logging while drilling LWD tool.

Abstract: A method for displaying a formation model while drilling a wellbore in the formation includes operating a well logging instrument at a measurement point in the formation along a wellbore while the wellbore is being drilled. Measurement data regarding the formation are obtained from the well logging instrument. An actual orientation of a geological structure is determined from the measurement data. A trajectory of the wellbore is displayed in three dimensions as it is being drilled through the formation. While drilling the wellbore, the geological structure is displayed along the trajectory of the wellbore according to the determined actual orientation of the geological structure. The actual orientation reflects an azimuth angle of planes corresponding to the geological structure. The trajectory of the wellbore is changed in response to displaying the determined actual orientation of the geological structure relative to the trajectory.

Abstract: Sensor assemblies including transmitter and receiver antennas to respectively transmit or receive electromagnetic energy. The sensor assemblies are disposed in downhole tools adapted for subsurface disposal. The receiver is disposed at a distance less than six inches (15 cm) from the transmitter on the sensor body. The sensor transmitter or receiver includes an antenna with its axis tilted with respect to the axis of the downhole tool. A sensor includes a tri-axial system of antennas. Another sensor includes a cross-dipole antenna system.